Will the 2022 compound heatwaveedrought extreme over the Yangtze River Basin become Grey Rhino in the future?

The increasingly frequent and severe regional-scale compound heatwave-drought extreme events(CHDEs),driven by global warming,present formidable challenges to ecosystems,residential livelihoods,and economic conditions.However,uncertainty persists regarding the future trend of CHDEs and their insights into regional spatiotemporal heterogeneity.By integrating daily meteorological data from observations in 1961-2022 and global climate models(GCMs)based on the Shared Socioeconomic Pathways,the evolution patterns of CHDEs were compared and examined among three sub-catchments of the Yangtze River Basin,and the return periods of CHDE in 2050s and 210Os were projected.The findings indicate that the climate during the 2022 CHDE period was the warmest and driest recorded in 1961-2022,with precipitation less than 154.5 mm and a mean daily maximum temperature 3.4°C higher than the average of 1981-2010,whereas the char-acteristics in the sub-catchments exhibited temporal and spatial variation.In July-August 2022,the most notable feature of CHDE was its extremeness since 1961,with return periods of~200-year in upstream,80-year in midstream,and 40-year in downstream,respectively.By 2050,the return periods witnessed 2022 CHDE would likely be reduced by one-third.Looking towards 2100,under the highest emission scenario of SSP585,it was projected to substantially increase the frequency of CHDEs,with return periods reduced to one-third in the upstream and downstream,as well as halved in the midstream.These findings provide valuable insights into the changing risks associated with forthcoming climate extremes,emphasizing the urgency of addressing these challenges in regional management and sustainable development.

Compound extreme inundation risk of coastal wetlands caused by climate change and anthropogenic activities in the Yellow River Delta,China

The coastal wetlands of the Yellow River Delta(YRD)in China are crucial for their valuable resources,environmental significance,and economic contributions.However,these wetlands are also vulnerable to the dual threats of climate change and human disturbances.Despite substantial attention to the historical shifts in YRD's coastal wetlands,uncertainties remain regarding their future trajectory in the face of compound risks from climate change and anthropogenic activities.Based on a range of remote sensing data sources,this study undertakes a comprehensive investigation into the evolution of YRD's coastal wetlands between 2000 and 2020.Subsequently,the potential fate of coastal wetlands is thoroughly analyzed through the Land Use/Cover Change(LUCC)simulation using System Dynamic-Future Land Use Simulation(SD-FLUS)model and the extreme water levels projection integrated future sea-level rise,storm surge,and astronomical high tide in 2030,2050,and 2100 under scenarios of SSP1-2.6,SSP2-4.5,and SSP5-8.5.Results revealed that YRD's coastal wetlands underwent a marked reduction,shrinking by 1688.72 km²from 2000 to 2020.This decline was mostly attributed to the substantial expansion in the areas of artificial wetlands(increasing by 823.78 km2),construction land(increasing by 767.71 km²),and shallow water(increasing by 274.58 km²).Looking ahead to 2030-2100,the fate of coastal wetlands appears to diverge based on different scenarios.Under the SSP1-2.6 scenario,the area of coastal wetland is projected to experience considerable growth.In contrast,the SSP5-8.5 scenario anticipates a notable decrease in coastal wetlands.Relative to the inundated area suffered from the current extreme water levels,the study projects a decrease of 6.8%-10.6%in submerged coastal wetlands by 2030 and 9.4%-18.2%by 2050 across all scenarios.In 2100,these percentages are projected to decrease by 0.4%(SSP2-4.5)and 27.1%(SSP5-8.5),but increase by 35.7%(SSP1-2.6).Results suggest that coastal wetlands in the YRD will face a serious compound risk from climate change and intensified human activities in the future,with climate change being the dominant factor.More effcient and forward-looking measures must be implemented to prioritize the conservation and management of coastal wetland ecosystems to address the challenges,especially those posed by climate change.

Advancing index-based climate risk assessment to facilitate adaptation planning:Application in Shanghai and Shenzhen,China

One of the key issues in climate risk management is to develop climate resilient infrastructure so as to ensure safety and sustainability of urban functioning systems as well as mitigate the adverse impacts associated with increasing climate hazards.However,conventional methods of assessing risks do not fully address the interaction of various subsystems within the city system and are unable to consolidate diverse opinions of various stakeholders on their assessments of sector-specific risks posed by climate change.To address this gap,this study advances an integrated-systems-analysis tool-Climate Risk Assessment of Infrastructure Tool(CRAIT),and applies it to analyze and compare the extent of risk factor exposure and vulnerability over time across five critical urban infrastructure sectors in Shanghai and Shenzhen,two cities that have distinctive geo-climate profiles and histories of infrastructure development.The results show significantly higher level of variation between the two cities in terms of vulnerability levels than that of exposure.More specifically,the sectors of critical buildings,water,energy,and information&communication in Shenzhen have significantly higher vulnerability levels than Shanghai in both the 2000s and the 2050s.We further discussed the vulnerability levels of subsystems in each sector and proposed twelve potential adaptation options for the roads system based on four sets of criteria:technical feasibility,flexibility,co-benefits,and policy compatibility.The application of CRAIT is bound to be a knowledge co-production process with the local experts and stakeholders.This knowledge co-production process highlights the importance of management advancements and nature-based green solutions in managing climate change risk in the future though differences are observed across the efficacy categories due to the geographical and meteorological conditions in the two cities.This study demonstrates that this knowledge co-creation process is valuable in facilitating policymakers'decision-making and their feedback to scientific understanding in climate risk assessment,and that this approach has general applicability for cities in other regions and countries.